1. Field
This invention relates generally to data communications, and more specifically, to a service gateway.
2. Background
Service gateways such as server load balancers, firewalls, or traffic managers are typically deployed to bridge services between client computing devices and application servers. The number of client computing devices proliferates in past few years in the areas of consumer computers, mobile computing devices, smartphones, and gaming devices.
When the number of client devices increases, the number of service sessions between client devices and application servers increases accordingly. Traditional stateful session packet processing used by service gateways gives way to stateless packet processing. Stateless packet processing is more efficient in computation and in memory consumption. It suits well in order to scale up services for an expected large number of service sessions. A typical stateless packet processing method uses a form of hash table. The table is stored with predetermined servers and applications information.
At the same time, the number of applications also increases rapidly as consumers and corporations install new applications on their computing devices. More servers are installed every day, and more applications become available every hour. In order to activate a server or an application in a server, operator needs to update the hash table with the additional server or application information. Often times, updating the table means replacing an existing server or application information of a table entry with the activating server or application information. Such table entry content replacement is disruptive to on-going service session using the existing table entry. Data packets of any on-going service session would not be forwarded to the proper server or client device. For example, if a consumer is watching a Netflix™ streaming video, the video stream will be abruptly stopped. If a corporate worker is in the middle of a business transaction, the transaction will be stalled. The worker needs to restart the transaction. In a worst case, the worker may need to find out which part of the transaction had been completed in order to avoid duplicating the completed portion of the transaction.
In addition to activating a new server or application, during maintenance such as backup, software update, hardware replacement, servers and applications are often taken off line. The corresponding table entries will also need to be replaced as the server or the application on a server is no longer available at the table entry. It is desirable to replace the table entry with a second server or another server running the same application.
It is highly desirable to have a stateless packet processing method while services can be managed to allow a server or an application on a server to be added or removed, without interrupting existing service sessions.
Therefore, there is a need for a method to manage services over a service gateway using stateless packet processing method.